This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
Devices for sealing and inflating inflatable objects are required, in particular for puncture repair kits, which are arranged in the motor vehicle and carried by it in place of a spare tire.
In the case of such puncture repair kits for the temporary repair of tire punctures, in which the compressor units, i.e. the air compressors for filling a damaged tire, usually by way of a valve-and-distributor unit for sealant and compressed gas, are connected to the tire to be repaired, the valve-and-distributor unit also has a connector for the connection of a sealant container. For sealing the damaged tire, the sealant is then fed by the air compressor into the tire by way of the valve-and-distributor unit and after that the tire is inflated by the air compressor up to a certain minimum pressure.
The compressor units, i.e. the air compressors, are usually produced partly or completely from plastic or similar low-cost materials. One of the most important technical challenges with this type of production is that the materials used have a temperature resistance that is limited, and lower in comparison with a metal, and have a low thermal conductivity.
Without implementing special protective measures, the heating of the air compressor that is caused by the compression/compression process may lead to thermal overloading of system components. This is the case in particular when there is prolonged uninterrupted use. Thermal overloading is most likely to occur here when the compressor is operated near its mechanical or electrical loading limit, for example when it pumps against maximum pressure over a prolonged time, when for instance air and viscous sealant are being fed into the tire through the tire valve.
In order to prevent such overloading in all operating states, in the prior art system components that are particularly at risk, such as for example the cylinder head in an air compressor formed as a reciprocating piston compressor, are produced from metal. However, this method leads to significantly increased production costs.
Another possibility is to permanently limit the power of the compressor. However, in terms of its application, this method leads to oversized air compressors, and therefore also significantly increases the production costs.
It is similarly possible to limit the temperature of system components that are at risk by means of active cooling, for example by fans. However, on account of the low thermal conductivity, this method can only be used to a qualified extent in the case of plastic components.